The present invention relates to magnetic storage devices and particularly to a method and apparatus for enabling a compact design of a magnetic storage device, particularly for a tape cartridge.
Tape cartridges are in extensive use today having substantially replaced storage of tape on open reels. The compact-cassette or "Philips type" cassette provides an opening in the front of the cassette for allowing the magnetic head of the magnetic tape drive to access the tape within. A separate plastic cover is supplied with the cartridge for dust protection due to the permanent opening in front of the cartridge.
Modern data cassettes for use with computers, such as the 1/4 inch data cartridge, incorporate an integral door so that the tape is protected when it is removed from the cassette protective case or dust cover. The door is hinged on one side of the cartridge, and the door is opened during loading of the cartridge into the recorder. Such cartridges and/or opening mechanism are disclosed, for example, in U.S. Pat. Nos. 4,622,606; 4,636,890; 4,984,111; and 5,323,280.
Door opening in data cassettes is typically accomplished in such a way that a part of a magnetic recorder pushes a small edge on an opposite side of the cassette door axis, causing it to pivot open. This design is useful for small openings, but for larger doors, this method generally requires excessive space and limits design flexibility for the mechanical design of the tape drive. Additionally, for small doors, a challenge is presented to accommodate the components of the magnetic tape drive in such a way that these components do not interfere with the opening of the door. This is especially true for tape drives where the cartridge is loaded into the tape drive sideways, that is, with a side of the cartridge perpendicular to the door leading the insertion of the cartridge into the tape drive.
Video cassettes also incorporate a door that protects the tape until the cartridge is inserted into the video tape recorder. Such a door is necessary due to a long span of tape located behind the door, which would otherwise be unprotected during the time period when the cartridge was removed from its protective dust cover until inserted into the video recorder. These cartridges must have the long span of tape on the front thereof due to the fact that the tape guiding mechanism is contained in the recorder, and that components of the guiding mechanism must be positioned behind the tape to withdraw the tape from the cartridge. Thus, access to the back of the tape is necessary so that the tape can be wrapped around a spinning video head drum.
During loading into the recorder, these cartridges are typically moved first inwardly and then downwardly for engagement with the hubs of the cartridge at the same time as the door is opened. The door opens in such a way that it is turned 90 degrees around an axis located near to the top cover. Thus, the door roughly follows a quarter of a full circle and ends in a position on the upper side of the cartridge. However, with the door in this position, the cartridge occupies an extra space compared to a cartridge with the door closed. Currently, the extra space for door opening is not of great concern in most videocassette drives since the extra space is available due to the above loading operation, particularly for the engagement movement with the tape hubs, i.e., the door opening space does not require additional space that is not otherwise needed for cassette loading. Such extra space requirement, however, may be a detriment in a drive which otherwise could more effectively use such wasteful extra space.